PTL 1 discloses an example where, by using, as a member for observing, in real time, a state in which a specimen is reacted with gas at a high temperature, an electron microscope or the like in which a specimen holder including a capillary tube for spraying gas toward a heater for heating the specimen is provided, such a gas reaction at the high temperature is observed. PTL 2 discloses an electron microscope in which gas is introduced in a horizontal direction, however, a specimen holder has openings for allowing electron beams to pass therethrough in a vertical direction. PTL 3 discloses an example where a capillary that can house a specimen has a rotation mechanism and is placed on a stage of the microscope.